Insulating Hvac Ducts In Attic

Duct insulation keeps air that s supposed to be cool cool and air that s supposed to be warm warm.

Insulating hvac ducts in attic.

Made from 1 to 2 inch thick sheets of rigid glass fiber and coated with an aluminum laminate for a moisture air barrier duct board comes in sections that fit together like metal ducts. If your ducts aren t insulated you re probably paying way more than you should to cool and heat your home. So logically the ducts deserve more not less insulation. When the attic is 20 f that insulation is addressing a delta t of 50 f.

Insulated ducts have been the standard for decades now. Look for signs of air leaks at seams or joints such. But the air in the ducts is facing a delta t of maybe 100 f or 120 f a greater delta t. Purchase duct wrap insulation that complies with the 2009 international energy conservation code iecc standards that specify an r value of 8.

Duct board much like the duct liner is also a fiberglass product. Put it in an attic full of blown insulation and you re forcing it to work harder to vent its heat. Obviously it s hard to install r 60 duct insulation. How to insulate your central air heating ducts.

Most attic ducts are insulated flex ducts that is flex ducts with r 6 or r 8 fiberglass insulation along with an exterior polyethylene jacket. Repeat to insulate the remaining ducts. Secure the insulation with short strips of foil tape. Install ductwork so that it is in direct contact with i e laying on the ceiling and or truss lower cords.

All the ducts are in the attic. Inspect the span of ductwork to be insulated. R 8 duct insulation 5 227 btu hour. This of course is a good thing.

Insulating hvac ductwork when insulating hvac ductwork use a foil faced fiberglass insulation with an r 6 or higher r value. The duct insulation should include a vapor barrier cover. According to rightsuite the software we use the supply ducts have about 560 square feet of surface area and the return ducts 101 square feet. When these ducts are exposed to exterior air the plastic jacket never gets cold enough to permit condensation because the hot attic air keeps the plastic jacket warm.

Looking at the cooling side only the additional load would be. Snap a plastic cap onto the duct end then slip the preformed insulation over the duct. Make sure the foil surface of the insulation is free of dust before applying the tape. When hvac ducts are installed in a vented attic in a dry climate bury the ducts in attic insulation to protect them from temperature extremes in the unconditioned attic space.

Use the type of metallic foil duct tape recommended by the insulation manufacturer to seal and hold the insulation in place. In addition to making the unit hard to get to for service high attic heat can trigger the. Use metal flex or fiber board ducts that are insulated to code. Duct liner isn t generally a diy installation and if your ducts already have liner you don t need to insulate the exterior.